Taking aim at refractive error

Globally, uncorrected refractive errors are the main cause of visual impairment. In this issue, we look at the World Health Organization's SPECS programme and the global data on refractive error. We also provide specific guidance on managing various refractive conditions, including hyperopia, myopia

G lobally, uncorrected refractive errors are the main cause of visual impairment. 1 This translates to millions of people being negatively impacted in their lives due to lack of access to services and spectacles, resulting in lost education and employment opportunities, lower productivity, and impaired quality of life.
There is an urgent need for community-based strategies to tackle the rising prevalence of refractive errors and ensure equitable access to eye care services for all individuals, regardless of age, gender, socioeconomic status, or geographical location.By the year 2050, it is estimated that half the global population will be affected by myopia; this, as well as the emergence of myopic macular degeneration as an increasing cause of vision impairment, will require a significant focus on preventative and treatment strategies.In addition, with the global population growing and people living longer, there will be a significant increase in the number of people who need near vision spectacles for presbyopia.
The Community Eye Health Journal has produced this issue on refractive errors to further build on the knowledge of the eye care community, to address the pressing needs of the estimated 1 billion people worldwide who have vision impairment because they do not have access to a pair of spectacles.Rapid action is needed, which is whyin 2021 -the World Health Organisation member states endorsed a global target to increase effective refractive error coverage (eREC) by 40 percentage points.
In addition to articles about global magnitude of refractive error and the WHO SPECS 2030 initiative to help countries develop a solution and meet the 40 percentage point target, readers can also find specific guidance on managing various refractive conditions, including hyperopia, myopia, and presbyopia.Each condition presents unique challenges and requires tailored interventions to optimise visual outcomes and enhance quality of life for those affected.
Good vision in older people has a significantly positive impact on their physical and mental health and their functional ability.NICARAGUA G lobally, uncorrected refractive errors are the main cause of visual impairment.1This translates to millions of people being negatively impacted in their lives due to lack of access to services and spectacles, resulting in lost education and employment opportunities, lower productivity, and impaired quality of life.
There is an urgent need for community-based strategies to tackle the rising prevalence of refractive errors and ensure equitable access to eye care services for all individuals, regardless of age, gender, socioeconomic status, or geographical location.By the year 2050, it is estimated that half the global population will be affected by myopia; this, as well as the emergence of myopic macular degeneration as an increasing cause of vision impairment, will require a significant focus on preventative and treatment strategies.In addition, with the global population growing and people living longer, there will be a significant increase in the number of people who need near vision spectacles for presbyopia.
The Community Eye Health Journal has produced this issue on refractive errors to further build on the knowledge of the eye care community, to address the pressing needs of the estimated 1 billion people worldwide who have vision impairment because they do not have access to a pair of spectacles.Rapid action is needed, which is whyin 2021 -the World Health Organisation member states endorsed a global target to increase effective refractive error coverage (eREC) by 40 percentage points.
In addition to articles about global magnitude of refractive error and the WHO SPECS 2030 initiative to help countries develop a solution and meet the 40 percentage point target, readers can also find specific guidance on managing various refractive conditions, including hyperopia, myopia, and presbyopia.Each condition presents unique challenges and requires tailored interventions to optimise visual outcomes and enhance quality of life for those affected.
Good vision in older people has a significantly positive impact on their physical and mental health and their functional ability.NICARAGUA provision of glasses, and other services.To support the implementation of vision screening for children, the WHO released the Vision and eye screening implementation handbook (bit.ly/WHOscreen).For specific guidance on the implementation of a school eye health programme, the IAPB is revising and updating its current guidelines.These new guidelines will be launched at the IAPB 2030 Insight Live event in June 2024; the current guidelines are available at bit.ly/IAPBschool

A vision for the future
We need to work together to ensure that no individual is left behind in their journey towards optimal vision and well-being.By advocating for policies that promote equitable access to eye care services, investing in training and capacity building initiatives, and fostering partnerships with local stakeholders, we can create sustainable solutions that address the systemic barriers to accessible and quality refractive error services and improve eye health outcomes.Through collaboration, innovation, and a shared commitment to excellence and integration, we can build more robust systems and healthier, more resilient communities for the future.U ncorrected refractive error is often ignored in the realm of global health priorities, yet its substantial impact on the economic and personal wellbeing of individuals and societies worldwide is undeniable.Myopia (shortsightedness), hyperopia (farsightedness), and astigmatism, grouped together under the term 'refractive error', cause blurred distance and/ or near vision, and presbyopia (age-related loss of accommodation) causes blurred near vision.Although presbyopia has a different mechanism to the other refractive errors, all these conditions can be corrected using spectacles or contact lenses.For the purposes of this article, therefore, we will use the term refractive error to refer to refractive error and presbyopia.
Unless refractive errors are corrected (using spectacles, contact lenses, or otherwise), the children and adults affected will experience difficulties in tasks that are crucial for daily living, education, and employment.
In this article, we summarise the estimated prevalence, the populations affected, and the implications if refractive error and optical services are not extended to everyone who needs them.We aim to equip policy makers and refractive error care providers alike to advocate for the resources required to tackle this global issue.

How big is the problem?
The estimates of global magnitude vary widely, due to relatively limited primary data and the different modelling assumptions made (see panel).
• Blindness due to uncorrected refractive error (defined as distance visual acuity worse than 3/60): the current estimate is 3.7 million 1,2 distribution, and reproduction in any medium for non-commercial purposes, provided that the copyright holders are acknowledged.

Disclaimer
Signed articles are the responsibility of the named authors alone and do not necessarily reflect the views of the London School of Hygiene & Tropical Medicine (the School).Although every effort is made to ensure accuracy, the School does not warrant that the information contained in this publication is complete and correct and shall not be liable for any damages incurred as a result of its use.
The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the School in preference to others of a similar nature that are not mentioned.The School does not endorse or recommend products or services for which you may view advertisements in this Journal.• Near vision impairment due to presbyopia (defined as near visual acuity worse than N6 at 40 cm): estimates range from 510 million 1,2 to 826 million. 3,4 total, up to 1 billion people worldwide, predominantly in Africa and Asia, are blind or have vision impairment because they do not have the spectacles they need. 1,2,3,4e prevalence and distribution of near and distance vision impairment due to uncorrected refractive error is expected to change significantly in coming decades, due in part to the rise of myopia, most rapidly in East Asia, and to a rise in presbyopia, due to population ageing.

Children and learning
Children are particularly vulnerable to the consequences of uncorrected refractive error.Children who do not receive adequate correction for their refractive error are at risk of lifelong visual impairment due to amblyopia.This not only affects the individual, but also stunts the development of entire communities and nations.In addition, uncorrected myopia and hyperopia can hinder academic progress, leading to lower educational attainment and future career opportunities.A myopic child who can't see the chalkboard may be misdiagnosed with learning disabilities.

Productivity and economic impact
Whereas cataract, the other leading cause of avoidable visual impairment, affects mostly older, non-working people, the impact of refractive error extends throughout the working-age population.Correcting refractive error increases productivity (by up to 32% 5 ) and reduces absenteeism and job losses.This results in substantial economic gains for individuals and nations.In low-and middle-income countries, where access to vision care is limited, the economic consequences of not treating individuals is especially severe.Uncorrected myopia leads to an estimated global productivity loss of US $244 billion 6 while presbyopia may be responsible for a loss of between US $25 billion 7 and US $54 billion. 8

Healthy ageing
Vision impairment has been associated with worse outcomes among older adults, including cognitive decline and dementia, 9 depression, 10 and increased risk of falls 11 and fracture, 12 all of which increase morbidity and mortality.
Refractive services therefore have the potential to not only improve vision and quality of life, but also to save lives.

Eye health equity
Access to eye care is often inequitable and vision impairment due to refractive error can make this worse, with rural and marginalised communities suffering the most.This is true both on a global scale and within communities.Globally, South Asia, South East Asia, and sub-Saharan Africa have the highest prevalence of uncorrected refractive error (standardised for age). 2 Within communities, prevalence is higher, and willingness-to-pay (a measurement of how much a person can afford to spend) for spectacles is lower, among those with lower incomes. 13,14Addressing refractive error is not just a matter of vision; it is a matter of social justice.It is about ensuring that everyone has the same opportunities for education, employment, and a high quality of life.Neglecting refractive error can worsen inequalities and social exclusion.

The role of refractive error care providers
Every eye care provider plays a crucial role in addressing this issue, whether on a local, regional, or global scale.Refractive service providers, usually led by optometrists, are the bridge between policy and practice: global health goals can only have a tangible impact if eye care workers are there to implement them.
Including eye care in general health care, and making spectacles for presbyopia available in the community (e.g., at pharmacies) is crucial given the scale of the problem; this is in line with WHO recommendations for the provision of presbyopia correction at the community level. 15Technology provides an opportunity to ease this transition by making it possible to train community and primary health care workers from a distance, provide decision support algorithms, and the potential for remote supervision or telemedicine input when needed.Tele-refraction is a growing field, although there is not yet enough evidence supporting its use .16

Advocating for resources
Policy makers must prioritise uncorrected refractive error as a part of their broader health and development agenda.Investing in refractive error and optical services not only improves the lives of individuals, but also promotes economic development.Access to affordable spectacles and regular eye examinations should be integrated into national health systems.

Promoting education and awareness
Refractive error care providers can help raise awareness about the importance of regular eye examinations and the availability of affordable corrective measures.They can also advocate for comprehensive school vision screening programmes to identify and address refractive error in children early, and they can offer workplace assessments for employees as a way to increase productivity and safety.Refractive error correction is also key to road safety: visual impairment has been found to be associated with a 46% greater risk of road traffic collision. 17

WHO SPECS 2030
In 2021, WHO member states endorsed a global target to increase effective refractive error coverage (eREC) by 40 percentage points.The World Health Organization has recently launched a new SPECS 2030 initiative, aiming to provide quality, affordable and people-centred refractive error services to everyone who needs them.

Conclusion
Near and distance vision impairment, due to uncorrected refractive error and presbyopia, is a global health issue with profound implications for individuals, communities, and nations.Stakeholders and health workers at all levels have a role to play in tackling this large, but solvable, problem.As policy makers and health service managers, the responsibility lies with you to allocate resources and prioritise refractive services in national health agendas.As refractive error care providers, the work you do restores not only your patients' eyesight, but also their education, income, and safety.

Recent global estimates of refractive error and presbyopia
These tables summarise some of the most widely accepted estimates of the magnitude of refractive error in recent years, and the studies on which these are based.Note that the Eliminating Poor Vision in a Generation Report uses a different threshold (visual acuity < 6/9), which has contributed to the large difference in reported magnitude.However, there remains a shortage of primary data on which to base estimates.Ongoing data collection via eye care programmes and surveys, such as Rapid Assessment of Avoidable Blindness (RAAB) surveys, should improve the accuracy of future estimates.

What are the key challenges to achieving the global 2030 target for refractive error?
There are many challenges to achieving the 2030 global target for refractive error.First, uncorrected refractive error tends to be much greater in populations that already have inadequate access to health care. 3econd, refractive error and optical services are commonly only available in the private sector, and therefore costs pose a major barrier. 4Other challenges include the insufficient availability of qualified personnel to carry out refraction and dispense spectacles, limited government oversight and clinical regulation, scarce services outside of urban areas, and low awareness and acceptance of spectacles among members of the public.

What is the WHO SPECS 2030 Initiative?
A comprehensive approach is needed to address these many long-standing challenges to increasing the coverage of refractive error services and -in particular -to strengthen provision in the government sector.The WHO SPECS 2030 Initiative calls for coordinated action amongst all stakeholders (public, private, non-profit, and philanthropy) across the following five pillars, in line with the SPECS acronym (Figure 1, in blue): G lobally, it is estimated that only around one-third of people with vision impairment due to refractive error have access to a pair of spectacles that can effectively address their refractive error and allow them to see well. 1 In recognition of the fact that uncorrected refractive error is the leading cause of near and distance vision impairment worldwide, and that spectacles are a very cost-effective intervention, a new global target for refractive error was endorsed at the World Health Assembly in 2021.Specifically, the global target is to increase the percentage of people with access to appropriate spectacles (known as effective coverage of refractive error, or eREC), by 40 percentage points

WHO SPECS 2030 -a global initiative to strengthen refractive error care
Coordinated global action is needed to improve access to refractive error services for everyone who needs it.
Spectacles improve access to education.KENYA Figure 1 The five strategic pillars of the WHO SPECS 2030 Initiative (in blue) and the country-level desired outcomes (in yellow).For each pillar, a set of country-level 'desired outcomes' have been defined by WHO, with input from the eye care sector, 5 that would facilitate a sustainable increase in refractive error coverage (Figure 1, in yellow).
The WHO SPECS 2030 Initiative aims to support the achievement of this target in four key ways.

Developing technical guidance and tools
This area of work will include, but is not limited to, the development of the following: • Guidance on legislative issues that impact on increasing spectacle coverage, for example, integration of refractive error services into primary health care • Models for competency-based teams for refractive error services • A costing tool to support country planning • Tools to strengthen monitoring and surveillance.

Engaging with regions and countries
This may include WHO-led policy dialogues with governments to develop or strengthen refractive error services that are part of health systems, countrylevel workshops and training for health planners and health care providers, or capacity building and awareness raising within WHO regional and country offices.

How to contribute to the WHO SPECS 2030 Initiative
Individuals who are involved in the provision and/or coordination of eye care are encouraged to advocate for the need to strengthen the provision of refractive services at all levels of the health system.To support this, a series of specific technical resources are available on the WHO SPECS 2030 website (www.who.int/initiatives/specs-2030).Additional resources will be added throughout 2024 and 2025.
Organisations and institutions can apply to become members of the Global SPECS Network.Further information regarding the eligibility criteria and how to apply can be found on the Global SPECS Network webpage (www.who.int/initiatives/specs-2030/global-specs-network).Myopia typically starts to develop in childhood and tends to progress to higher levels until adulthood.The earlier myopia starts, the more likely a child will end up with high levels of myopia, which puts them at greater risk of complications, such as myopic maculopathy, which may result in loss of vision.Whilst any level of myopia may cause complications, the risk increases with increasing levels of myopia. 1

Who is at risk?
Those who are most at risk of developing myopia are children who spend less time outdoors and more time indoors on near tasks, children who have higher levels of education, and children who have parents with myopia.People of East Asian ethnicity are also at higher risk.

Impact of myopia
If left uncorrected, poor vision in childhood can hinder school performance and wellbeing.Quality of life is affected in people with higher levels of myopia and people with myopia-related complications.Given the progressive nature of the condition, myopia has a financial impact on the families of affected individuals and on society, due to the health expenditure related to the costs of managing the condition as well as costs related to eye examinations, corrective devices, and lost productivity.
The rising prevalence of myopia is expected to strain eye care, health, and education systems.Vision loss due to myopia may result in productivity loss and the resulting economic burden may be significant for those countries with a higher prevalence of myopia.

Prevention
Due to the progressive nature of myopia, preventing or delaying the onset is currently the most effective way to tackle the burden of myopia .

It is well established that increasing time outdoors can
greatly reduce the risk of developing myopia.Therefore, the current recommendation is that children should spend at least 2 hours outside each day to prevent or delay the onset of myopia. 2 Public messages about the prevention of myopia is the responsibility of all stakeholders, including researchers, clinicians, health bodies, and governmental authorities.To achieve widespread public awareness, various channels of communication such as engaging with parents and carers, involvement in community groups and schools, as well as print and social media campaigns should be considered.

Treatment
Once myopia has been diagnosed, it is possible to offer treatment that not only corrects visual symptoms, but also slows progression.(Note: a comprehensive eye examination for children should include cycloplegia if possible; see the article on cycloplegia in this issue).
There are a growing number of management options that have been shown to be effective at slowing the progression of the condition, including:

What can we do about myopia? An evidence-informed approach
Prevention is vital to reduce the number of people with myopia, and management strategies are effective in reducing the progression of myopia and decreasing the risk of sight-threatening complications.
By 2050, it is estimated that half the world's population will have myopia.NEPAL © RABINDRA ADHIKARY CC BY-NC-SA 4.0 "Myopia typically starts to develop in childhood and tends to progress to higher levels until adulthood."lens designs).The latter is usually limited to one line reduction in the peripheral treatment areas of the spectacle lenses.
Although complications with contact lenses and orthokeratology are rare, they include microbial keratitis and infiltrates, with daily disposable wear minimising such risks.
The safety of low-level red-light therapy requires further study, although known side effects involve temporary after-flash images and rare cases of retinal damage that resolved without lasting effects.

A note on rebound
With myopia control treatments involving higher doses of atropine and red-light therapy, an accelerated increase in myopia has been reported once these treatments are stopped.This effect, known as rebound, tends to be more pronounced in initial months after treatment is stopped.To mitigate rebound, a tapered approach is recommended, although the efficiency of tapering methods needs further evaluation.
With optical strategies, studies with orthokeratology indicate some rebound when switching from orthokeratology to single vision lenses, but no rebound was reported with contact lenses or spectacles.

Conclusion
In conclusion, prevention of myopia through lifestyle changes is still the most effective way to address this growing problem.Myopia management approaches have been growing and have proven to be effective in reducing the risk of myopia progression.Data and modelling indicate that various approaches have the potential to positively influence outcomes for individuals as well as benefit society at large.Ongoing research and advancement will continue to shape the future landscape for myopia prevention and management.For clinical guidelines, it may be useful to refer to optometry and ophthalmology associations.They have an obligation to stay up to date and their purpose is to help clinicians -look to your local associations for relevant local guidelines.They do vary, and some suggest referral pathways.In addition to clinical efficacy, there are several other factors that will guide the choice, implementation and success of myopia management options, including: • The availability of different interventions in your country, and whether they have been approved by professional and regulatory bodies.
• The cost of interventions, and patients' ability to pay for them.
• How acceptable the interventions are to patients.
This could depend on comfort and visual performance, for example.
• How familiar practitioners are with the different myopia control strategies, and how confident they feel about implementing them.

Are these treatments safe and comfortable?
Overall, adverse events associated with various myopia control strategies have been reported to be minimal, although more data is needed to establish the safety of light therapy.
Using atropine at concentrations higher than 0.01% may cause side effects such as increased pupil size, accommodation paralysis, photophobia, glare, and blurred near vision, but these effects are reversible when treatment is stopped.
Due to the optical design features needed for spectacles and contact lenses used in myopia control, visual disturbances have been reported, which vary with lens design.These include haze and ghosting (with multifocal contact lenses) and reduced visual performance in the periphery (with certain spectacle How is the effectiveness of myopia control strategies measured?
The effectiveness of interventions to slow myopia progression can be measured by observing the change in refractive error, measured in dioptres, or the change in axial length, measured in mm.
Effectiveness is often reported as 'relative efficacy'.In these studies, the progression of refractive error (in dioptres) in the group using the myopia intervention is compared with the progression in a control group of children using standard single-vision spectacles or contact lenses.Because control groups can differ between studies, it is important to be cautious when using this measurement to compare different treatment options.
Another approach to measuring the effectiveness of interventions is to compare myopia control strategies to the natural eye growth observed in non-myopic (emmetropic) eyes.Axial length measurements are also considered more accurate than refractive error measurements for assessing progression.Presbyopia is the most common cause of vision impairment globally, impacting 1.8 billion people. 1 Almost every person will experience presbyopia if they live into their 50s and beyond.
Presbyopia is addressed with the use of near-vision spectacles.These are commonly called 'ready-made' reading glasses, reading spectacles, or readers, although they have many uses in addition to reading.These spectacles are critical for people with presbyopia who rely on their ability to see close-up to work, read, learn, and perform day-to-day tasks and activities.People who also have problems with distance vision or astigmatism may need combined distance and near vision correction in the form of bifocal or progressive lenses, for example.

The impact of unaddressed presbyopia
According to the World Health Organization's World Report on Vision 1 (based on research by Fricke et al. 2 ), more than 1 billion people have a vision impairment that could have been prevented or is yet to be addressed.Of these, more than 800 million people are estimated to be visually impaired due to uncorrected presbyopia and need only reading spectacles to be able to see clearly. 1 It is estimated that 90% of people with uncorrected presbyopia live in low and middle-income countries.Without proper reading spectacles, they are being driven deeper into poverty as their blurred vision inhibits their ability to work, causing them to lose their jobs and livelihoods.Addressing presbyopia therefore presents a significant opportunity to improve income, productivity, and quality of life for hundreds of millions of people worldwide.Because it can be corrected at low cost with vision screenings and ready-made reading spectacles, presbyopia can and should be addressed on a much larger scale.
For people with presbyopia, receiving ready-made reading spectacles leads to positive changes in livelihoods, worker productivity, income, health, opportunities for education and lifelong learning, and overall well-being.In a randomised controlled trial (RCT), tea pickers who received reading spectacles were up to 32% more productive in their jobs than their peers in the control group. 3In another RCT, workers across a range of visually intensive jobs saw their incomes increase by nearly US $12 a month, an increase of 33.4%. 4 In comparison, providing reading spectacles at scale can cost as little as US $2 per person, including programme costs (based on RestoringVision's 2023 programmes, which reached 4 million people in 106 countries); making it a highly cost-effective intervention.
Many occupations require near vision, including tea and coffee pickers, textile workers, artisans, tailors, weavers, community health workers, midwives, mechanics, carpenters, plumbers, barbers, people who braid hair, and people who rely on their mobile phones for their livelihoods.In addition, in our work, many people have reported significant improvement in their quality of life when they are again able to read their holy scriptures and texts, communicate effectively through their mobile phones with family and friends, and engage in other activities that require near vision.

A global issue
There is a growing understanding that uncorrected presbyopia and other forms of refractive error are a critical public health issue.Accordingly, World Health Organization (WHO) member states set an ambitious target to increase effective refractive error coverage by 40 percentage points by 2030.To accelerate the achievement of this target, WHO developed the SPECS 2030 initiative, 5 which seeks to mobilise coordinated action across governments, civil society, and the private sector to increase spectacle coverage, especially in low and middle-income countries.The United Nations General Assembly also called for improving eye health and access to spectacles among its member states in a 2021 resolution, recognising the importance of eye health in achieving the Sustainable Development Goals. 6 What can be done?
Two key actions are needed: 1 Integrating presbyopia screening and correction at the community and primary care level 2 Aligning policies to support and accelerate the provision of spectacles for presbyopia 1. Integrating presbyopia screening and correction at the community and primary care level WHO recommends that presbyopia correction is provided at the community and primary eye care level. 7 In our experience, vision screening programmes to address presbyopia can readily be embedded within government and nongovernmental programmes and systems across a range of sectors, including health, education, agriculture, pensions, and social protection.This integration is a promising way to address presbyopia at scale, which can have an immediate and sustained impact in the lives of people reached and accelerate achieving the SPECS 2030 goal of increasing effective refractive error coverage.Due to the cost-effectiveness of programmes addressing presbyopia, these programmes can be implemented at scale.Several near vision testing methodologies can be used, including WHOeyes (bit.ly/WHOeyes), a new free mobile app by WHO, or a printed near vision eye chart with text, numbers, or symbols (like tumbling Es).
If a person's primary complaint is difficulty seeing at near distances (close-up), and the vision test confirms this, they can be given a pair of good quality, low-cost, ready-made reading spectacles to correct their vision impairment.If the individual presents with other eye conditions or concerns, they can be referred for a full eye examination.
Addressing presbyopia in this way can bring many people into the eye health care system for the first time.This provides a key opportunity to identify other critical eye conditions such as cataracts, glaucoma, or diabetic retinopathy, which are more prevalent in the age group of people typically affected by presbyopia.
Presbyopia programmes can also play an important role in building public awareness and understanding of wider eye health issues and risks.In our work, we have found that these programmes demonstrate the extent of visual impairment due to refractive error and the value of addressing this.In turn, this can lead to greater interest in the strengthening of comprehensive eye care programmes and greater allocation of resources for this purpose.

Aligning policies to accelerate the provision of spectacles for presbyopia
In many high-income countries, reading spectacles are sold 'over the counter' at low cost in shops and pharmacies, making them accessible and affordable to people who only need near vision correction.However, in many other parts of the world, including low and middle-income countries, reading spectacles are inaccessible and unaffordable for hundreds of millions of people, often due to policies that affect the cost of these spectacles, and how and where they can be provided.
There are two types of policies that can support addressing presbyopia on a larger scale.
1 Policies on who can screen and dispense.Many countries do not require reading spectacles to be dispensed only by trained eye health professionals.Instead, these spectacles can be provided by people with basic training in screening and dispensing or they can be made more widely available, so that individuals can select and purchase the pair that suits their visual needs. 2 Policies on importing near vision spectacles.
Many countries allow the importation of reading spectacles duty-free or at a lower rate to ensure that these health products are accessible and affordable.This is an effective way to facilitate scaling up the response to presbyopia.
Unfortunately, a significant number of countries with very large populations of people with uncorrected presbyopia have not yet adopted these policies.It is recommended that these countries revise their policies in order to accelerate their achievement of the 40 percentage point increase in effective coverage for refractive error as outlined by WHO. 5 © AARON TELFORD CC BY-NC-SA

What about the need for a comprehensive eye examination?
While there is consensus on the benefits of a comprehensive eye examination -every person should ideally have one every 1-3 years, depending on their age and health status -the number of optometrists and ophthalmologists in low-and/or middle-income countries is insufficient to meet the needs of the population.For example, fourteen low-and/or middle-income countries have fewer than one ophthalmologist per 1 million people, and another 31 countries have only 1-3 ophthalmologists per 1 million people.Ophthalmologists and optometrists also tend to be concentrated in urban areas. 8 these contexts, it is not feasible (or affordable) for everyone who needs a pair of reading spectacles to consult with an ophthalmologist or optometrist.Until the workforce can catch up with the need, it is vital for people to be screened and gain access to this essential product in a way that promotes overall eye health, as it can be the difference between someone sustaining their livelihood or not.

Access to reading spectacles can increase people's productivity and earnings. VIET NAM
Unless their hyperopia is corrected by the age of 7 years, children with clinically significant uncorrected hyperopia (defined as ≥+2.00D) are also at risk of developing strabismus and amblyopia, resulting in irreversible visual impairment in the affected eye. 5,6

Screening for hyperopia
Because screening for hyperopia is challenging, children with clinically significant hyperopia are often not identified or treated.At present, the distance visual acuity (VA) test is the main method used in school-based programmes in low-and middle-income countries to identify children with reduced vision.This test is useful in detecting myopia, but not always hyperopia, as only some children with clinically significant hyperopia experience reduced distance vision.
Given the fact that the majority of a child's visual development is thought to happen by the age of 7 years, it is important to detect and treat clinically significant hyperopia as early as possible.However, in settings with limited resources, it is usually recommended to do this when children start school.
There is no globally accepted consensus on how to screen children for hyperopia.We recommend using either the plus-lens test or the near visual acuity test to screen for significant hyperopia, but only if there are enough resources and well-trained personnel to carry out the tests.

The plus lens test
The plus lens test involves putting a +2.50 D lens in front of the eye and measuring the difference (if any) in distance visual acuity.
Because children with hyperopia can see more clearly through a plus lens, especially at near distances, the addition of a plus lens should not affect their distance visual acuity very much (Figure 2a).Children who do not have hyperopia, however, will experience significant blurring of their vision when looking through the same lens (Figure 2b).
H yperopia, also called farsightedness, is a common problem in children worldwide.The limited data available suggest that around 4.6% of children, on average, have clinically significant hyperopia (defined as a spherical equivalent of ≥+2.00 D), ranging from 2.2% in Southeast Asia to 14.3% in the Americas. 1peropia affects the eye's ability to focus, especially at near distances.This happens when the eyeball is too short, or the cornea is not curved enough, causing the rays of light to focus behind the retina instead of on it.Babies are usually born moderately hyperopic, but this gradually decreases as their eyes grow and develop: from an average spherical equivalent of +2.00 D at age 3 months, to just over +1.00 D by the time they are 3 or 4 years old. 2,3ildren with adequate focusing ability (accommodation) can often overcome uncorrected hyperopia, including clinically significant hyperopia (defined as ≥+2.00D).When these children start attending school, however, the need to accommodate for longer periods of time can lead to eye strain, headaches, and blurred vision, which can affect their reading and other school-related tasks.Children who have higher levels of hyperopia that cannot be overcome using their accommodative ability experience poorer near vision and near depth perception, which also affects their academic performance. 4Some children may even experience poorer distance vision due to hyperopia.

Hyperopia: a practical introduction
Hyperopia is a common eye condition in children that affects near vision.Detecting and treating it in time can reduce the risk of squint and amblyopia.To distinguish between children with and without clinically significant hyperopia, the criteria for failing or passing the test are as follows: Fail (child has hyperopia): The distance visual acuity while looking through +2.50 D lens worsens by two lines or less compared to the unaided distance visual acuity.

Pass (no hyperopia):
The distance visual acuity while looking through the +2.50 D lens worsens by more than two lines compared to the unaided distance visual acuity.
How to perform the plus lens test 1 After completing the unaided distance visual acuity test, cover the left eye and place a +2.50 D lens over the child's right eye. 2 Direct the child's attention to the distance vision chart and check their visual acuity again, by asking them to identify the letters or symbols.3 Decide whether the child has passed or failed, using the criteria above.4 Repeat for the other eye.

The near visual acuity test
The near visual acuity test involves measuring the near distance vision.To distinguish between children with and without clinically significant hyperopia, the criteria for failing or passing the near visual acuity test are as follows: Fail (child has hyperopia): If the child is unable to correctly identify 3 out of 5 letters or symbols on the 0.2 LogMAR (or 6/9.5 Snellen) line.

Pass (no hyperopia):
If the child is able to correctly identify 3 out of 5 letters or symbols on the 0.2 LogMAR (or 6/9.5 Snellen) line.
The steps are as follows: 1 Use a near visual acuity chart, such as a Sloan letter or Lea symbol chart; the latter is helpful for children who are not comfortable with the alphabet.
2 Hold the near visual acuity chart at 40 cm from the face, at eye level (Figure 1).Ensure that the child is not leaning forward.3 Cover the left eye with an occluder or patch and test the right eye. 4 Ask the child to identify the letters or symbols on each line, as directed.5 Decide whether the child has passed or failed the test, using the criteria mentioned earlier.6 Repeat for the other eye.

Prescribing for hyperopia
To determine the amount of hyperopia, it is advisable to conduct a cycloplegic refraction whenever possible, as it yields reliable measurements (see article on cycloplegic refraction in this issue).
When prescribing spectacles for hyperopic children, the aim is to decrease the demand for focusing (accommodative demand) and provide clear and comfortable vision with both eyes.Therefore, eye care providers should prescribe the maximum plus power that children can comfortably accept while still maintaining clear vision.Factors to consider include the child's age, the amount of hyperopia in each eye, and the presence of strabismus, among others.In most cases, children are better able to tolerate a lower plus prescription, except when there is an inward eye turn (esotropia).In such cases, the full cycloplegic correction is required to minimise or eliminate the squint.
It is also important to recognise that children with anisometropia (a difference in refractive error between the eyes) of +1.00 D or greater, or who have a similar level of hyperopia (isometropia) of +5.00 D or greater in both eyes, are at risk of hyperopic refractive amblyopia. 7,8The American Academy of Ophthalmology has practical guidelines for these children, according to age and other factors (see Table 1)."To determine the amount of hyperopia, it is advisable to conduct a cycloplegic refraction whenever possible." Tropicamide 1% is fast acting and has a shorter duration but has a weaker cycloplegic effect, so it is better suited to older children.While tropicamide has been shown to yield similar refraction results to cyclopentolate, care needs to be taken in cases of high hyperopia, strabismus, or when there is inconsistency between examination results and clinical manifestations of vision problems. 3th types of drops are safe, with cyclopentolate reporting some extremely rare side effects. 4Systemic absorption can be minimised by occluding the puncta after instillation and wiping away any excess drops.
Where cyclopentolate is not available, or in children with known sensitivity, central nervous system disorders, or Down syndrome, tropicamide is a viable alternative. 5 Atropine 1% is commonly used in some settings, but caution is advised.Atropine is slow acting and has a longer duration with effects lasting several days; this can cause discomfort.In children with very darkly pigmented eyes, atropine is often recommended when cyclopentolate is not effective.Note that atropine can be poisonous when absorbed systemically: a 3 g tube of 1% atropine ointment can be fatal if ingested accidentally by a small child. 6

When is cycloplegic refraction needed?
Ideally, all children with suspected refractive errors should undergo cycloplegic refraction at least once when they are identified, and subsequently when it is suspected that the child is accommodating during refraction.However, there are legislative limitations in many countries as to who can use pharmaceutical agents for eye examinations, with the use of diagnostic eye drops often restricted to medical doctors only.
T he prevalence of uncorrected refractive errors in children is on the rise globally. 1ncorrected refractive errors can affect children's ability to develop good vision and also hamper their education and social activities.It is therefore important to measure a child's refractive errors accurately.
Accommodation is the ability of the eye to focus on objects at varying distances.This ability is greatest in children and declines with age -usually becoming noticeably reduced after the age of 40 with the development of presbyopia, when the eye loses the ability to focus on near objects.
Children's wonderful ability to accommodate can, however, affect the accuracy of refractive error assessment: children often try too hard to give the 'correct' answers, which leads them to subconsciously over-focus, resulting in an inaccurate spectacle prescription.Typically, myopia will be overcorrected, and hyperopia (long-sightedness) will be undercorrected; astigmatism could also be misdiagnosed.Children could therefore be prescribed unnecessary spectacles for myopia or astigmatism, or miss out on getting spectacles to correct hyperopia.Wearing incorrectly prescribed spectacles could lead to non-optimal vision, eye strain, headaches, nausea, strabismus (squint), and amblyopia (lazy eyes), and it could even hasten myopia progression. 2 order to achieve accurate results, accommodation can be controlled by using cycloplegic eye drops to temporarily paralyse the muscles used in accommodation, followed by retinoscopy (known as wet retinoscopy) or subjective refraction (wet refraction).
Commonly used eye drops for this purpose are cyclopentolate, tropicamide, and atropine.
Cyclopentolate 1% (0.5% for children aged less than 1 year) is accepted as the gold standard for cycloplegic refraction.It is fast and relatively short acting and is suitable for most patients.For more practical tips on instilling eye drops in a young child, visit tinyurl.com/CEHJ-eyedrops.

A need for advocacy
Atropine and tropicamide are widely approved for use in low-and middle-income settings.
Cyclopentolate is less widely approved, but it is listed as an alternative to atropine and tropicamide in the WHO Model List of Essential Medicines 23rd List (2023).
To address the increasing demand for accurate refraction in children, we need to advocate for legislation that would allow qualified and appropriately trained eye health professionals, such as optometrists, to use the best cycloplegic agent (cyclopentolate).This is especially important given the increased prevalence of refractive errors in children, particularly myopia.
Where the use of pharmaceutical agents is not allowed, alternative methods of controlling accommodation (such as fogging lenses for retinoscopy or refraction) may be considered, although these may be less effective .7,8In older children (aged 11-18 years), conducting retinoscopy without cycloplegia (dry retinoscopy) may provide satisfactory results.However, if any of the indications listed in the panel are present, and dry refraction does not yield reliable results, then cycloplegic refraction is indicated.

How to perform cycloplegic refraction in school-aged children
Children often do not like drops in their eyes, and cycloplegic drops can be particularly uncomfortable.
Although some eye care providers suggest instilling an anaesthetic eye drop before instilling the cycloplegic eye drop, in our experience instilling a single drop (just the cycloplegic agent) is less stressful for the child.
The following steps are designed to be reassuring for the child and to support their cooperation with the process of cycloplegic refraction.
1 Wash your hands and explain to the child and/or their caregiver what you are going to do.We recommend telling the child that the drops may make their eyes feel 'funny'; avoid using the word 'sting.' 2 Ask the child to sit on their parent or carer's lap; this is often the most comfortable place for the child.3 Ask the child to look up.As shown in Figure 1, gently pull the lower eyelid down to create a 'sac' (the lower fornix).Instil one drop of cyclopentolate 1% (or tropicamide 1%, if cyclopentolate is not available) into the lower fornix.4 Wipe away any excess drops and gently press a finger against the inner corner of the eye, next to the nose, to occlude the puncta for 1-2 minutes.This will minimise systemic absorption.5 Repeat steps 3 and 4 in the other eye.6 If, after 15 minutes of instilling cyclopentolate, the pupils do not appear to be dilating, and the child has darkly pigmented eyes, instil another drop and repeat punctal occlusion for 1-2 minutes.

Other indications for cycloplegic refraction
Cycloplegic refraction can be helpful in the following circumstances.Refer to your professional association's guidelines for more detailed recommendations.
• Undiagnosed manifest esotropia • An esotropia recognised by the parent or carer • Unstable or uncompensated esophoria • Significant risk factors for esotropia or amblyopia, such as family history or high refractive errors • Good visual acuity is not achieved following a dry refraction • Stereoscopic acuity is poor • Latent hyperopia or pseudomyopia is suspected.

A
'person-centred' approach to refractive error assessment shifts the focus from treating just a refractive error or medical condition, to treating the patient as a whole person.Every person is different, so we, as practitioners, need to tailor our approach to meet the individual needs of each patient. 1 In low-and middle-income countries, more than 1 in every 8 people have a significant disability. 2 In this article, we show how you can adapt your refractive error assessment process for adults with a range of sensory, physical, or cognitive differences (alone or in combination), which may not be immediately obvious and which the patient may not tell you about.

Types of challenges
Patients can present with a range of challenges.
For example, challenges such as reduced mobility, abnormal head posture, motor coordination issues, and/or difficulties in maintaining a fixed gaze in a certain direction may make it difficult for the patient to see the eye chart.
Being deaf or hard of hearing, or having cognitive impairment, anxiety, or attention difficulties may make it difficult for the patient to understand and respond to questions, or to follow instructions.

Before the examination begins
• Ensure that the examination room is fully accessible to people who use a wheelchair.
• Observe the patient entering the room.Greet them and invite them to sit down.This is an opportunity to objectively assess the patient's physical abilities and restrictions, as well as their ability to understand and follow instructions.
• Allow the patient some time to familiarise themselves with the room and the equipment.
• When the patient is settled, introduce yourself and talk to the patient in a friendly way.
• Ask a few introductory questions, such as their name, how they are, and whether they are comfortable.
• Ask the patient if they have any communication preferences.Alternatively, if you notice that they have difficulties understanding you (e.g., due to being deaf or hard of hearing, or having cognitive difficulties) ask how you can make things easier for them (see panel) • If the patient's support person is acting as an interpreter, continue to speak to the patient directly and maintain appropriate eye contact -do not address the support person instead of the patient.

Taking a history
• Ideally, you will have received information about the patient ahead of the assessment appointment.Some organisations request that patients or their support persons complete a form in the weeks leading up to the appointment, such as this one by the charity SeeAbility: www.seeability.org/resources/aboutme-and-my-eyes.If no information is available, and you have time, it may be worth contacting the patient or support person by phone before the appointment to get a brief history.

How to assess refractive error in adults with additional or complex needs
Being flexible, calm, and sensitive to patients' needs and abilities is key to offering a patient-centred eye examination.

How to support communication and interaction with the patient
Understanding how best to communicate with your patient is vital.Ask the patient if they have any communication preferences, then allow enough time for them to answer.
When your patient is deaf, hard of hearing, non-verbal, is from a different language group, or has other communication challenges, it is important to speak clearly and slowly.If patients rely on lip reading, remove your face mask (if safe to do so), and ensure that the patient can clearly see your face when you are speaking to them.Avoid making the room too dark, and don't position yourself in front of a bright light or bright window.
If patients have cognitive difficulties, speak slowly and use short, simple sentences.You can also use gestures or pictures to explain procedures and choices, if needed.
Always speak with the patient directly, even if they have an interpreter (e.g. a sign language interpreter).Never assume that the patient cannot understand you, and don't talk about the patient to the interpreter or support person, as if the patient isn't there.• Ask about their current prescription (if any) and whether they are able to function as they would like to, in terms of both distance and near visual tasks.Do they have any other visual symptoms?
• Ensure that patients have enough time to answer your questions before moving them on to the next question.It is important that the patient feels that you understand their needs and that you want to help them.
• A useful general question with which to end history taking is, 'Is there anything else you want to tell me?'

The examination
Being patient and flexible throughout the examination will help you to adapt your approach based on the patient's responses and needs.Remember to allow enough time for patients to follow instructions and answer questions.
For ease of examination, specific equipment and techniques may be needed.
Before testing visual acuity, find out whether patients are familiar with the alphabet; they may be more comfortable using Lea or Kay symbols or a tumbling E chart; matching cards can also be helpful.In terms of the objective refractive routine, retinoscopy is a vital skill and may be the only way to assess refraction for patients with significant physical or intellectual challenges.Cycloplegia may be recommended in young adults -see the article in this issue.If a dark room is anxiety-provoking for the patient, it is fine to keep the light on.Using loose trial lenses or a lens rack can also help to speed up the assessment.Obtaining an accurate result from this part of the routine will reduce the time spent on the subjective refraction, which will reduce the patient's fatigue.
You can simplify the subjective refraction routine by using larger differentials in power (e.g.plus or minus 1:00 D) or fewer lens choices; this can help to make the subjective examination more meaningful.Where possible, ask questions that are easy to understand.For example, ask if the lenses reduce blur, or help the patient to see smaller letters.Moving the chart or patient closer may be helpful, particularly in cases of abnormal head posture and those with visual impairment.A 3-metre test chart is useful, and using a logMAR chart will help you to account for different working distances.When assessing astigmatism, a 1:00 DC Jackson cross cylinder (used with an appropriate visual target), with the cylinder moved in 20-degree steps, will help patients with visual impairment discriminate differences more easily.
People with additional needs are more likely to need help with near vision.When assessing near vision in someone who is unable to communicate, dynamic retinoscopy can be very useful. 3It is important that any significant distance refractive error is corrected first, and that dynamic retinoscopy is done without cycloplegia.
If a patient can communicate the clarity of their near vision, then you can carry out a subjective near vision assessment.You can refine in 0.5 D or 1.00 D steps to elicit the most appropriate add at the preferred working distance.Remember that the level of clarity needed is determined by the near vision tasks a patient performs.Perfect near vision is not always needed.
If the patient is of presbyopic age (usually over the age of 40), their age can be used to estimate the likely starting point for the level of add needed. 4 patients with low vision, a high reading add of +4.00 D or more can be used; however, the shorter working distance needs to be emphasised.Base-in prisms need to be considered to aid convergence for higher adds.A low vision aid may be more appropriate, this might require referral to a low vision service.

After the examination
It is important to involve the patient in the decisionmaking process following the findings of the refractive examination.For example, if they require both near and distance vision correction, would they prefer to have different spectacles for each type of task, or would bifocal/ progressive lenses work better for them?See the article on patient education in this issue for more information.
Respect patients' preferences and consider their capabilities when suggesting solutions.If needed, additional recommendations around lighting, colour, and contrast may also be helpful to enable patients to make the most of their sight in different environments.
It may be useful to write down your findings to help the patient and/or support person remember your recommendations; for example, detailing which spectacles or low vision aid is used for each visual task, while also checking the availability and affordability of each device, and explaining where to get it and what funding may be available to help with the costs, if needed.
In order to plan follow-up, it is very important to understand the patient's circumstances in coming for their eye examination.For example: Have they come from a long distance?Has their support worker needed to give up a day's paid work in order to accompany them?Has the visit created a large financial burden?Can the patient be seen locally, or is a mobile eye team visit planned to the patient's area?
Provide clear instructions for any follow-up care, together with contact details in case there are any further questions; this will help to reduce anxiety and make it possible to address any issues that may come up in future.

Tips for reducing patients' anxiety
• Allow enough time for the examination so that you are not rushed.
If you are calm, the patient is more likely to feel calm.
• It may be helpful to modify the testing environment to suit the patient's needs.For example, you can change the lighting (not too bright, and not too dark), reduce distractions, and plan or suggest breaks from testing.
• Explain each step of the examination process as you perform them, in simple, non-technical language -this helps to build trust.You can do this even if you're not sure how much the patient understands.
• If the patient has a cognitive impairment, a useful way to reduce their anxiety can be to carry out an examination task or test on their support person first; this helps them to feel more familiar with the situation and understand what is expected.

Measuring pupillary distance
The first step in achieving correct alignment of the optical centre is to accurately measure and record the pupillary distance, measured in millimetres (mm).Depending on the circumstances and the patient (see panel) this can be either the binocular pupillary distance (the distance between the centres of the two pupils), or the monocular pupillary distance: the distance between the centre of the pupil and the centre of the nose, recorded for each eye separately (see panel).
These are the measurements the laboratory will use when fitting lenses to the patient's chosen frame.
If the pupillary distance is measured incorrectly, the optical centre will be incorrectly set within the spectacle frames, which can only be rectified by remeasuring the pupillary distance correctly, and remaking the spectacles.

NOTE:
It is important to guide patients in their choice of frame.If the frame is too big or too small, or if it has been poorly adjusted, this can lead to misalignment of the optical centre, even when the pupillary distance has been measured correctly.

What you will need:
• A pupillary distance ruler Before you begin: • Wash your hands and tell the patient what you are going to do.
• Position yourself directly in front of the patient, ensuring that you are at the same height as them, and about an arm's length in distance.

Measuring the binocular pupillary distance
1 Holding the ruler between your thumb and forefinger, place the ruler so that it is resting on the bridge of the patient's nose and forehead.Use your middle finger to steady your hand on their head.2 Close your right eye and ask the patient to look towards your open left eye.
T he optical centre (OC) of a spectacle lens is the point at the centre of the lens through which light rays pass without any unwanted prismatic effects (displacement of the image).In other words, the optical centre of a lens is the point at which the wearer will experience the clearest vision.
It is therefore crucial for the optical centre to be correctly aligned with the wearer's pupils, so they can see clearly, no matter which direction they look in.If the optical centre is not correctly aligned, light rays that pass through the lens are refracted, or bent, which leads to blurred or distorted vision.This can cause the patient to experience eye strain, discomfort, and headaches.
The optical centre also plays an important role when prism is prescribed, usually for patients who have difficulty combining the images received from both eyes.Prisms can be created by decentring the lens in the frame; i.e., moving it so that the patient looks through the lens at a point away from the optical centre.

Michelle Mehta
Lecturer in Optometry and Visual Sciences: City, University of London, London, UK.

Prescribing and fitting spectacles: the role of pupillary distance and the optical centre
To ensure clear vision, it is vital that the optical centre and pupils are aligned correctly.

Monocular or binocular pupillary distance?
It is standard practice to measure and record both monocular and binocular PDs for each patient.Monocular PD is often recommended for greater accuracy in prescribing because most people have asymmetrical faces; i.e., our left and right pupils are not always the same distance from the centre of our nose.This asymmetry can result in wrong placement of the optical centre and induces prismatic distortion.

M
any people feel apprehensive when they are first told that they need a pair of spectacles.
Here are some common examples we have come across, and ideas for addressing them.
• Long-term use of spectacles.Some patients feel if they wear spectacles for a long time their eyes may become sunken; reassure them that spectacles do not affect the anatomy of the eye.
• Cosmetic appearance.Some patients worry that the spectacles may not look good on their face; the person dispensing should provide a mirror to the patient while selecting the frames so they can reassure themselves about their appearance.
• Effect of spectacles on vision.Some patients are hesitant to wear spectacles, claiming that their vision might deteriorate.Assure them that the spectacles will improve their sight and that wearing corrective lenses will not make their vision worse in the long term.

When dispensing spectacles
It is normal for people to experience some initial discomfort when they start wearing spectacles.Without the correct information and support, some patients may stop wearing their spectacles before they can benefit from the improvements in their vision the spectacles provide.
Therefore, when patients try on their new spectacles, take a moment to talk to them about the following (as appropriate): • Peripheral blurring due to the frame.Some patients may experience blurring in their peripheral vision due to the edge of the frame.Reassure them that this effect becomes less noticeable over time • Depth perception.Patients may experience temporary issues with depth perception whilst their eyes adjust to the new corrective lenses.Reassure them that they will adjust to this quickly.
• Distortion.This may be noticed more with strong prescriptions; patients may report a 'fishbowl' effect or other visual distortions which make them feel uncomfortable or disoriented, particularly if it's a new prescription or a different lens design.Again, assure them that this will becomes less noticeable over time, as they adjust.

Before patients take their spectacles home
Ideally, patients should return for a check-up after one year.Explain to patients that they may need to come back sooner if they are unable to adjust to the prescription, if the spectacles break, or if they notice a change in their vision.Some patients believe that spectacles 'expire' after a certain amount of time.Before the patient goes home, explain that the lens, when properly taken care of, will continue to work.Any changes in vision they experience may be due to scratches on the lens surface, or because there has been in a change in their vision.
Encourage patients to care for their spectacles (see panel) and to return for eye tests at regular intervals, depending on the nature of their condition.Remind patients to avoid sharing spectacles with relatives or friends as the prescription will be different and the user is likely to experience worsened vision and other symptoms, such as headaches or dizziness, as a result.

Patients who need correction for both distance and near vision
Some patients may have specific visual requirements for both close work (such as reading or sewing) and distance vision (such as driving or seeing objects that are far away).
There are two main options for these patients: 1 Prescribing two (or more) separate pairs of spectacles -e.g., one for near vision and one for distance vision. 2 Prescribing bifocal (Figure 4) or progressive lensesthese provide two or more optical powers in a single lens, so that the patient has more than one working distance.Bifocal lenses have a visible horizontal line where the two lens powers meet; in progressive lenses there are no visible lines.

Leah Kennan
Ophthalmic nurse: City Eye Hospital City, Nairobi, Kenya.

Talking to patients about their new spectacles
Educating patients, listening to their concerns, and offering guidance and reassurance will enhance their overall experience of wearing spectacles.
Put spectacles on and take them off using both hands to avoid tension on one side of the frame.KENYA    Lensmeter.Also known as lensometer or focimeter, it is used to measure the prescription of a pair of eyeglasses.For more information read our article, 'Understanding and caring for a lensmeter' (tinyurl.com/CEHJ-lensmeter).
Ready-made spectacles.These pre-made glasses have the same powered lens on each side and can be dispensed immediately.These are useful where limited resources do not permit custom-made spectacles.
Retinoscope (Figure 2).This is a handheld instrument which shines a light into the eye -the reflection is observed and used to assess the amount of refractive error.It provides an objective method of refraction in which the patient does not need to tell the practitioner what they see.For more information, read our article, 'Understanding and looking after a retinoscope and trial lens set' (tinyurl.com/CEHJ-retino).
Autorefractor.A computerised device which can be used to objectively estimate a person's refractive error.Care needs to be taken when using these devices, particularly with children, as the accuracy of the results can be affected by accommodation.

General care and maintenance
To ensure the proper operation, and to get the longest life from your refractive error devices, there are some essential practices that you should follow.3 Cleaning lenses and optical surfaces.Many ophthalmic devices have optical components such as windows, lenses, mirrors, filters, and prisms; these need to be protected and cleaned.For more information read our article, 'How to care for and clean optical surfaces' (tinyurl.com/CEHJ-cleanopt).
4 Prevention of fungal growth on optical components.In hot and humid climates, it is common for mould to grow on the surfaces of optical components.Precautions should be taken to prevent this.For more information read our article, 'Fungus: how to prevent growth and remove it from optical instruments' (tinyurl.com/CEHJ-fungus).
5 Bulb maintenance.Many devices used in eye care rely on light bulbs or lamps for their operation.All light bulbs have a limited lifespan, and when the bulb fails the device becomes unusable.Therefore, knowing how to handle, inspect, and replace bulbs is important.Always maintain a supply of replacement bulbs for your equipment and only use those recommended by the manufacturer.For more information read our article, 'How to handle and care for bulbs in ophthalmic equipment' (tinyurl.com/CEHJ-bulbs).
6 Fuse maintenance.Fuses play an important safety role in preventing damage to equipment due to electrical overloading and reducing the risk of electrical shock to patients and staff.For more information read our article, 'Checking and replacing fuses' (tinyurl.com/CEHJ-fuses).
7 General electrical safety practices.For more information read our article, 'Electrical safety in the clinical environment -good habits to maintain' (tinyurl.com/CEHJ-electric).The Barpeta Vision Centre was set up in February 2022 as a partnership between Mission Jyoti, a Mission for Vision initiative, and Sri Sankaradeva Nethralaya, an eye hospital in Guwahati in the north-eastern state of Assam, India.Its aim is to address the burden of visual impairment in Barpeta, a remote district of Assam, by offering affordable primary eye care services.
Before the vision centre was established, people with refractive errors could access services only during the cataract screening camps organised by Sri Sankaradeva Nethralaya, or by traveling 90 km to the nearest tertiary eye centre in Guwahati.People who needed spectacles had to buy them from local optical outlets at rates that were unaffordable for the majority.
The vision centre serves a population of about 50,000 and is located in rented premises with an area of 340 square feet, in the market area of Barpeta town.People from surrounding villages, within a radius of 15 to 20 km, come to Barpeta market for various purposes and can then also access eye care facilities at the vision centre.The vision centre also organises two or three community camps each month in villages within a radius of 5-8 km from Barpeta.During these camps, screening, identification, and referral services are provided.Patients identified with cataract are referred to the tertiary eye centre in Guwahati for surgery, and those who require spectacles and/or further examination are referred to the vision centre in Barpeta.
For the local communities, the distance to be covered and travel time required to access services such as basic eye examination, refraction test, identification of cataract and other conditions, and dispensing of spectacles have therefore been considerably reduced.

Human resources
The vision centre is staffed by an optometrist and two female community health workers.It is overseen by a co-ordinator who is responsible for managing other community activities conducted by Sri Sankaradeva Nethralaya in the area.
The community health workers and the co-ordinator are trained by, and affiliated to, the tertiary eye facility in Guwahati.The clinical staff are trained as part of a university-recognised course at Sri Sankaradeva Nethralaya.
The community health workers conduct door-todoor screening and refer patients as needed; interact with various stakeholders such as heads of schools, teachers, staff of primary health centres, and local community leaders; and organise community eye camps and vision screening programmes in schools.The female health workers interact with women during the door-to-door visits, talk to them about the vision centre and its services, and create awareness among women about the need for eye care for themselves and their children.

Reference 1 GBD
2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study.Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study.Lancet Glob Health.2021;9(2):e144-e160.
We rely on subscriptions and donations from charities and generous individuals to carry out our work.To support us, visit: www.cehjournal.org/donateor contact Anita Shah: admin@cehjournal.orgPublished by the International Centre for Eye Health, London School of Hygiene & Tropical Medicine.Unless otherwise stated, authors share copyright for articles with the Community Eye Health Journal.Illustrators and photographers retain copyright for images published in the journal.Please note that some articles are published online first and may have been shortened to fit the available space in this printed edition.Unless otherwise stated, journal content is licensed under a Creative Commons Attribution-NonCommercial (CC BY-NC) license which permits unrestricted use, COMMUNITY EYE HEALTH JOURNAL | VOLUME 37 | NUMBER 122 | 2024 3The Community Eye Health Journal is supported by: GLOBAL HEALTH • Moderate or severe distance vision impairment due to refractive error (defined as distance visual acuity worse than 6/18 but equal to or better than 3/60): estimates range from 123.7 million 3 to 157 million1,2

• S :
Improve access to refractive Services • P: Build capacity of Personnel to provide refractive services • E: Improve population Education • C: Reduce the Cost of refractive error services • S: Strengthen Surveillance and research.

Finally,
private sector representatives are encouraged to join the SPECS Private Sector Dialogues already mentioned, for which registration will open in mid-2024.For more information, please contact the WHO Vision and Eye Care Programme (vision@who.int).Refractive error services should be available to all, regardless of the type of health condition or impairment an individual may have.-sightedness -is a significant problem around the world.Currently, one in three people on the planet have myopia; by the year 2050, it is estimated that one in every two individuals will be affected.

•
Eye drops containing low concentrations of atropine • Light-based therapies • Combination treatments, involving one or more of these categories.Research into the efficacy of different myopia control interventions is ongoing, 3 which makes it challenging to stay up to date with the latest scientific evidence.Several organisations and professional bodies have developed resources to help clinicians make evidence-informed decisions about myopia control for their patients.The IMI's reviews of evidence, published as open access white papers (tinyurl.com/IMI-whitepapers)have been summarised in a 2-page infographic, available at myopiainstitute.org/myopia-infographics/The World Council of Optometry (WCO) has developed a 'Standards of Care' guideline (bit.ly/WCOstandard) and a practical guide to managing children with myopia (bit.ly/4agfYxu).

Figure 1
Figure 1 Measuring near visual acuity with a conventional LogMAR near vision chart using Lea symbols at 40 cm.ZIMBABWE

Figure 2b A
Figure 2bA child who does not have hyperopia will experience significant blurring of their vision when looking through a +2.50 D lens.

"7
Children are eager to please and they may try too hard to give the 'correct' answers during refraction; this can result in an inaccurate spectacle prescription.PAKISTAN © SHAFFAQ BAJWA CC BY-NC-SA 4.0 Wait 30-40 minutes (15-25 minutes for tropicamide 1%), then check that the pupils are dilated and do not constrict when light from a torch is shone onto them.If the pupils constrict, wait another 5 minutes and check reactivity to light again.8 When the pupils are unreactive to light, perform retinoscopy or subjective refraction.9 Advise parents that the child will have dilated pupils, blurry vision up close, and sensitivity to bright light for several hours afterwards.

Figure 1 Figure 2 References 1
Figure 1Gently pull down the lower eyelid to create a 'sac'.UK Note: Measuring visual acuity might not be possible or vital, so this can be elicited by asking what sort of tasks the patient does and what they can normally see.Think about what you are trying to achieve for the patient.

Figure 1
Figure 1 Marking the position of the pupil on dummy lenses.MOZAMBIQUE

Figure 2 Figure 3 Figure 4
Figure2The optical centre has been located using a focimeter

Figure 2
Figure 2 How to store spectacles in a case: lenses down, with the arms uppermost.

Figure 1
Figure 1 Use a microfibre cloth.Avoid using clothing, tissues, or paper towels as these can scratch the lens surface.

Figure 3
Figure 3 Place the spectacles on a surface with the lenses facing upwards.

1
General cleaning − Some surfaces may be damaged by harsh cleaners and alcohol.Only use the cleaning solutions recommended by the manufacturer.− Keep instruments covered when not in use. 2 Battery maintenance.Batteries should be managed to ensure that medical devices are always ready for use.Here are a few tips: − Follow manufacturer guidelines.− Store the battery separately from the device if is not being used for a long time.− Keep an inventory of spare batteries.

Figure 2
Figure 2 Components of a streak retinoscope

Table 1
Global estimates of the number of people with distance vision impairment or blindness due to refractive error (uncorrected, corrected, and total).

Table 2
Global estimates of near vision impairment due to presbyopia.

3. Motivating the private sector to make long-term contributions WHO
resbyopia is the age-related deterioration of a person's near vision, making it difficult to focus clearly on reading materials or other nearby objects.It typically begins around age 40 due to a loss of elasticity of the lens of the eye.Near vision continues to deteriorate until about the age of 60 to 65, when the condition stabilises.

Table 1
The American Academy of Ophthalmology's recommended prescribing guidelines for hyperopia.Available at tinyurl.

com/AAOhyperopia For children with isometropia (similar level of refractive error in both eyes)
(Source: AAO

Prescribing guidelines for hyperopia) For children with anisometropia (an unequal level of refractive error between the eyes)
(Source: AAO Prescribing guidelines for hyperopia)

Table 1
When to measure monocular and binocular pupillary distance